Dropper applicators are well known. One common type may be an elongated cylindrical tube, opened at a first and a s second end. The first end is fitted with a flexible bulb or some type of bellows. In use, the second end is immersed in a fluid. When the bellows is expanded, fluid is drawn into the elongated cylinder through the second end. When the bellows is collapsed, fluid is ejected from the elongated cylinder thought the same end.
Treating products with light is known. Products are treated with light for various reasons. For example, it is known to treat water with light to kill germs. It is also known to use light to cure dental adhesives. Light has been used to initiate chemical reactions that may not occur in the absence of light. Light has been used a reagent or catalyst in many chemical and biological reactions.